Artificial Daphnia medium: ADaM (Aachener Daphnien Medium)

We grow Daphnia in artificial medium. The original recipe for the medium was developed by Klüttgen, B., Dülmer U., Engels, M. & Ratte H. T. 1994. ADaM, an artificial freshwater for the culture of zooplankton. Water Research 28:743-746. We use a modified version of this medium (altered Seleniumdioxid concentration). To produce a given amount of medium add the amounts of sea salt and stock solutions as given in the following table.

Container with ADaM

60 l medium tank in our lab

Water Sea salt [gram] Stock solution A (ml) Stock solution B (ml) Stock solution C (ml)
10 l 3.33 23 22 1
50 l 16.6 115 110 5
60 l 19.9 138 132 6

We use a special sea salt which is produced by combining all chemical to make up the mixture. (Most commercially available sea salt is produced by evaporation of water from sea water. In this case, some of the salts do not solve anymore once put back into water). We buy this sea salt from an aquarium supply company. Atrificial sea salt works fine.

These are the concentrations for the three stock solutions:

Stock solution Chemical Concentration [g/l]
A CaCl2 x 2H2O 117.6
B NaHCO3 25.2
C SeO2 0.07

Some notes on our experience with this medium:

  • We use 60 liter plastic tanks to prepare the medium (see picture). The salts do not harm the plastic. It is better to use non-transparent material to prevent growth of algae.
  • We produce the medium 24 hours in advance, but shorter time periods don't really seem to harm the Daphnia.
  • The tanks are constantly aerated. The air passes through a filter with 0.2 μm pores. This prevents small particles and microbes to enter the water. Note that this saturates the medium with gas. If the medium warms up you get small gas bubbles in the water, which may cause the Daphnia to float on the water surface. If your animals have this problem allow the medium to stand still for a day before you use it.
  • We keep the stock solutions in a fridge and had never problems with older solutions.
  • If the tanks are used over longer period, you may get some growth of fungi, bacteria and/or algae on the walls. We clean the ADaM tank regularly to keep this down.
  • We have good experience with this medium culturing Daphnia magna, pulex, longispina, galeata and other, as well as other Cladocera.
  • If you have problems culturing Daphnia or other cladocerans in this medium, try to add some natural water (lake, stream, spring water). Adding 20% spring water we had good experience with clones which were tricky to keep otherwise.